The disclosures herein relate generally to an edge mountable connector for a printed circuit board and more particularly to support the connector so that solder tails are positioned for surface mount soldering to the board without the need for clamps or fixtures.
In the process of attaching an edge mountable connector to a printed circuit board (PCB), a circuit board panel supports the PCB by means of frangible members which interconnect the panel and peripheral or edge portions of the PCB. One of the edge portions of the PCB includes an array of solder pads which interconnect with conductive paths on the PCB. Immediately adjacent the solder pads, an enlarged cut-out portion is provided for inserting the connector. The connector includes a plurality of solder tails. When the connector is inserted into the cut-out portion, the solder tails are aligned in contact with the solder pads so that a subsequent soldering operation can provide the required connection between the aligned tails and pads.
Preferably, placement of the connector in position for soldering is accomplished by pick-and-place automation. To assure the success of the automated procedure, certain conditions must be satisfied. First, the connector must be seated in the cut-out portion so that the solder tails are aligned with the solder pads. This orientation or registration of tails-to-pads is part of the pick-and-place automation operation. Second, placement of the connector in the cut-out requires some means of seating the connector so that it does not drop completely through the cut-out. A prior solution to this problem included the placement of ears on opposite ends of the connector. The ears extend from the connector and seat on a top surface of the panel adjacent the cut-out, thus suspending the connector body within the cut-out. Next, the connector must be seated and supported in the cut-out so that the solder tails are on the same plane as the solder pads placing the tails and pads in contact preparatory to the actual soldering step. To satisfy this requirement, one approach has been to provide a seating surface on the ears which engages the panel top surface such that the connector is supported within the cut-out at a level which places the solder tails and solder pads in planar contact. Last, due to the center of gravity (CG) of the connector being off center (i.e. a substantial mass of the contacts is housed within the connector and displaced from the solder tail portion of the contact) the connector has a tendency to tip away from the PCB while it is supported on the panel by the ears. The tipping therefore causes the solder tails to tip up and out of contact with the solder pads. This is because the CG is displaced from the ears. As a result, clamps and fixtures must be applied to maintain the seated connector in the proper position so that the solder tails remain in contact with the solder pads for the soldering operation. These clamps and fixtures are manually applied thus defeating the complete automation of the procedure.
A limitation of using ears to support the connector in the cut-out is that due to the demand for a variety of connectors, each with solder tails at different offsets from the connector body centerline, many different offsets are required of the ear geometry. Incorporating interchangeable ear height features in mold tooling presents technical difficulties and/or is economically not feasible. It is usual, in the injection molding process, to gate on the end of an ear. Thus, building a mold with quick-change features for ear height adjustment requires the added expense of providing many gate inserts and increases changeover time. Furthermore, some desirable tail offsets would require decreasing ear thickness which would also decrease the gate area to the point of preventing proper mold fill. Another tooling disadvantage is that the ears can provide a bearing surface for ejecting the connector body from the mold. Thus, mold complexity is greatly increased when variable ejector positions, resulting from variable ear geometry, must be included in interchangeable tooling.
Therefore, what is needed is an apparatus and method for supporting a connector within a cut-out in a manner which orients the solder tails in planar position and contact registration with the solder pads for completing the soldering operation, which avoids connector tipping and the need for clamps and fixtures, and which also avoids the limitations and complexities associated with molding and ejecting the connectors of varying geometry and the associated tooling problems and expenses connected therewith.